code: def get_open_and_close(day, early_closes):
      market_open = pd.Timestamp(
          datetime(
              year=day.year,
              month=day.month,
              day=day.day,
              hour=9,
              minute=31,
          ),
          tz="US/Eastern",
      ).tz_convert("UTC")
      # 1 PM if early close, 4 PM otherwise
      close_hour = 13 if day in early_closes else 16
      market_close = pd.Timestamp(
          datetime(
              year=day.year,
              month=day.month,
              day=day.day,
              hour=close_hour,
          ),
          tz="US/Eastern",
      ).tz_convert("UTC")
  
      return market_open, market_close
  
file_path: zipline/zipline/utils/tradingcalendar.py
imports: import pandas
  import pytz
  from datetime import datetime
  from dateutil import rrule
  from functools import partial
label_desc: Use image node_id 5 for calling a global function with example usage: get_open_and_close(day, early_closes) and returns: market_open,  market_close